From: Arnd Bergmann <arnd@arndb.de>
To: "Theodore Ts'o" <tytso@mit.edu>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Dave Chinner <david@fromorbit.com>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
joseph@codesourcery.com, john.stultz@linaro.org,
hch@infradead.org, tglx@linutronix.de, geert@linux-m68k.org,
lftan@altera.com, linux-fsdevel@vger.kernel.org, xfs@oss.sgi.com
Subject: Re: [RFC 11/32] xfs: convert to struct inode_time
Date: Mon, 02 Jun 2014 14:52:13 +0200 [thread overview]
Message-ID: <15496653.1vSv1RUCC0@wuerfel> (raw)
In-Reply-To: <20140602115737.GB14276@thunk.org>
On Monday 02 June 2014 07:57:37 Theodore Ts'o wrote:
> On Mon, Jun 02, 2014 at 12:56:42PM +0200, Arnd Bergmann wrote:
> >
> > I think you misunderstood what I suggested: the intent is to avoid
> > seeing things break in 2038 by making them break much earlier. We have
> > a solution for ext2 file systems, it's called ext4, and we just need
> > to ensure that everybody knows they have to migrate eventually.
> >
> > At some point before the mid 2030ies, you should no longer be able to
> > build a kernel that has support for ext2 or any other module that will
> > run into bugs later....
>
> Even for ext4, it's not quite so simple as that. You only have
> support for times post 2038 if you are using an inode size > 128
> bytes. There are a very, very large number of machines which even
> today, are using 128 byte inodes with ext4 for performance reasons.
>
> The vast majority of those machines which I know of can probably move
> to 256 byte inodes relatively easily, since hard drive replacement
> cycles are order 5-6 years tops, so I'm not that concerned, but it
> just goes to show this is a very complicated problem.
One stupid question about the current code:
static inline void ext4_decode_extra_time(struct inode_time *time, __le32 extra)
{
if (sizeof(time->tv_sec) > 4)
time->tv_sec |= (__u64)(le32_to_cpu(extra) & EXT4_EPOCH_MASK)
<< 32;
time->tv_nsec = (le32_to_cpu(extra) & EXT4_NSEC_MASK) >> EXT4_EPOCH_BITS;
}
#define EXT4_EINODE_GET_XTIME(xtime, einode, raw_inode) \
do { \
if (EXT4_FITS_IN_INODE(raw_inode, einode, xtime)) \
(einode)->xtime.tv_sec = \
(signed)le32_to_cpu((raw_inode)->xtime); \
else \
(einode)->xtime.tv_sec = 0; \
if (EXT4_FITS_IN_INODE(raw_inode, einode, xtime ## _extra)) \
ext4_decode_extra_time(&(einode)->xtime, \
raw_inode->xtime ## _extra); \
else \
(einode)->xtime.tv_nsec = 0; \
} while (0)
For a time between 2038 and 2106, this looks like xtime.tv_sec is
negative when ext4_decode_extra_time gets called, so the '|=' operator
doesn't actually do anything. Shouldn't that be '+='?
Arnd
next prev parent reply other threads:[~2014-06-02 12:52 UTC|newest]
Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-30 20:01 [RFC 00/32] making inode time stamps y2038 ready Arnd Bergmann
2014-05-30 20:01 ` [RFC 01/32] fs: introduce new 'struct inode_time' Arnd Bergmann
2014-05-31 7:56 ` Geert Uytterhoeven
2014-05-31 8:39 ` Andreas Schwab
2014-05-31 13:19 ` Geert Uytterhoeven
2014-05-31 13:46 ` Andreas Schwab
2014-05-31 14:54 ` Arnd Bergmann
2014-05-31 16:15 ` Geert Uytterhoeven
2014-05-31 9:03 ` H. Peter Anvin
2014-05-31 14:53 ` Arnd Bergmann
2014-05-31 14:55 ` H. Peter Anvin
2014-05-30 20:01 ` [RFC 02/32] uapi: add struct __kernel_timespec{32,64} Arnd Bergmann
2014-05-30 20:18 ` H. Peter Anvin
2014-05-31 15:09 ` Arnd Bergmann
2014-05-30 20:01 ` [RFC 03/32] fs: introduce sys_utimens64at Arnd Bergmann
2014-05-31 9:22 ` Andreas Schwab
2014-05-31 14:55 ` Arnd Bergmann
2014-05-30 20:01 ` [RFC 04/32] fs: introduce sys_newfstat64/sys_newfstatat64 Arnd Bergmann
2014-05-30 20:01 ` [RFC 05/32] arch: hook up new stat and utimes syscalls Arnd Bergmann
2014-05-30 20:01 ` [RFC 06/32] isofs: fix timestamps beyond 2027 Arnd Bergmann
2014-05-31 7:59 ` Geert Uytterhoeven
2014-05-31 8:47 ` H. Peter Anvin
2014-05-30 20:01 ` [RFC 07/32] fs/nfs: convert to struct inode_time Arnd Bergmann
2014-05-30 20:01 ` [RFC 08/32] fs/ceph: convert to 'struct inode_time' Arnd Bergmann
2014-05-30 20:01 ` [RFC 09/32] fs/pstore: convert to struct inode_time Arnd Bergmann
2014-05-30 21:14 ` Kees Cook
2014-05-30 20:01 ` [RFC 10/32] fs/coda: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 11/32] xfs: " Arnd Bergmann
2014-05-31 0:37 ` Dave Chinner
2014-05-31 0:41 ` H. Peter Anvin
2014-05-31 1:14 ` Dave Chinner
2014-05-31 1:22 ` H. Peter Anvin
2014-05-31 5:54 ` Dave Chinner
2014-05-31 8:41 ` H. Peter Anvin
2014-05-31 15:46 ` Nicolas Pitre
2014-06-01 19:56 ` Arnd Bergmann
2014-06-01 20:26 ` H. Peter Anvin
2014-06-02 11:02 ` Arnd Bergmann
2014-06-02 1:36 ` Nicolas Pitre
2014-06-02 2:22 ` Dave Chinner
2014-06-02 7:09 ` Geert Uytterhoeven
2014-06-02 10:56 ` Arnd Bergmann
2014-06-02 11:57 ` Theodore Ts'o
2014-06-02 12:38 ` Arnd Bergmann
2014-06-02 13:15 ` Theodore Ts'o
2014-06-02 12:52 ` Arnd Bergmann [this message]
2014-06-02 13:07 ` Theodore Ts'o
2014-06-02 15:01 ` Arnd Bergmann
2014-06-02 14:52 ` H. Peter Anvin
2014-06-02 15:04 ` Chuck Lever
2014-06-02 15:31 ` Theodore Ts'o
2014-06-02 17:12 ` H. Peter Anvin
2014-06-02 18:50 ` Arnd Bergmann
2014-06-02 22:29 ` Theodore Ts'o
2014-06-02 22:32 ` H. Peter Anvin
2014-06-02 23:32 ` Theodore Ts'o
2014-06-02 23:33 ` H. Peter Anvin
2014-06-03 13:09 ` Roger Willcocks
2014-06-02 18:52 ` Arnd Bergmann
2014-06-02 18:58 ` Roger Willcocks
2014-06-02 19:04 ` Chuck Lever
2014-06-02 19:10 ` Arnd Bergmann
2014-06-01 0:39 ` Dave Chinner
2014-06-02 14:00 ` Joseph S. Myers
2014-05-31 15:37 ` Arnd Bergmann
2014-06-01 0:24 ` Dave Chinner
2014-06-02 0:28 ` Dave Chinner
2014-06-02 11:35 ` Roger Willcocks
2014-06-02 11:43 ` Arnd Bergmann
2014-06-03 0:32 ` Dave Chinner
2014-06-03 7:33 ` Arnd Bergmann
2014-06-03 8:41 ` Dave Chinner
2014-06-03 9:16 ` Arnd Bergmann
2014-05-30 20:01 ` [RFC 12/32] btrfs: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 13/32] ext3: " Arnd Bergmann
2014-05-31 9:10 ` H. Peter Anvin
2014-05-31 14:32 ` Arnd Bergmann
2014-05-30 20:01 ` [RFC 14/32] ext4: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 15/32] cifs: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 16/32] ntfs: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 17/32] ubifs: " Arnd Bergmann
2014-06-02 7:54 ` Artem Bityutskiy
2014-05-30 20:01 ` [RFC 18/32] ocfs2: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 19/32] fs/fat: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 20/32] afs: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 21/32] udf: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 22/32] fs: convert simple fs to inode_time Arnd Bergmann
2014-05-30 23:06 ` Greg Kroah-Hartman
2014-05-30 20:01 ` [RFC 23/32] logfs: convert to struct inode_time Arnd Bergmann
2014-05-30 20:01 ` [RFC 24/32] hfs, hfsplus: " Arnd Bergmann
2014-05-31 14:23 ` Vyacheslav Dubeyko
2014-05-30 20:01 ` [RFC 25/32] gfs2: " Arnd Bergmann
2014-06-02 9:52 ` Steven Whitehouse
2014-05-30 20:01 ` [RFC 26/32] reiserfs: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 27/32] jffs2: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 28/32] adfs: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 29/32] f2fs: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 30/32] fuse: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 31/32] scsi: fnic: use current_kernel_time() for timestamp Arnd Bergmann
2014-05-30 20:01 ` [RFC 32/32] fs: use new inode_time definition unconditionally Arnd Bergmann
2014-05-31 14:30 ` [RFC 00/32] making inode time stamps y2038 ready Vyacheslav Dubeyko
2014-06-03 12:21 ` Arnd Bergmann
2014-05-31 14:51 ` Richard Cochran
2014-05-31 15:23 ` Arnd Bergmann
2014-05-31 18:22 ` Richard Cochran
2014-05-31 19:34 ` H. Peter Anvin
2014-06-01 4:46 ` Richard Cochran
2014-06-01 4:44 ` Richard Cochran
2014-06-02 13:52 ` Joseph S. Myers
2014-06-02 19:19 ` Arnd Bergmann
2014-06-02 19:26 ` H. Peter Anvin
2014-06-02 19:55 ` Arnd Bergmann
2014-06-02 21:57 ` H. Peter Anvin
2014-06-03 14:22 ` Arnd Bergmann
2014-06-03 14:33 ` Joseph S. Myers
2014-06-03 14:37 ` Arnd Bergmann
2014-06-03 21:38 ` Dave Chinner
2014-06-04 15:03 ` Arnd Bergmann
2014-06-04 17:30 ` Nicolas Pitre
2014-06-04 19:24 ` Arnd Bergmann
2014-06-05 0:10 ` H. Peter Anvin
2014-06-10 9:54 ` Arnd Bergmann
2014-06-02 21:02 ` Joseph S. Myers
2014-06-04 15:05 ` Arnd Bergmann
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